Sales promotion is a well-known retail technique, aiming at increasing revenues, attracting customers, encouraging purchase at certain hours, accelerating the sales of manufacturer-promoted products, reducing the inventory of rapidly-aging or slow-selling products and the like. An effective sales-promotion method is the Sale, which is a temporary price-reduction on specified items. Sales prove to attract customers, boost purchase of on-Sale items and create an atmosphere which encourages purchase of other items as well.
A typical store comprises a store computer system having therein inventory and price information, communicating with a number of points of sale (POS) which identify the items included in a purchase, calculate their price and collect payment. Items offered for sale are usually displayed on shelves, and a shelf label with price information relating to each group of identical items is usually positioned adjacently to each such group. Electronic shelf labels are shelf labels communicating with the store computer system for synchronizing the information displayed thereon with the prices charged at the POS. Electronic shelf labels are deployed commercially and are described in a number of U.S. Pat. Nos. (e.g. 4,002,886, 4,139,149, 4,521,677, 4,766,295, 5,019,811 and 5,313,569.). The communication between the store computer and the electronic shelf labels uses hard wiring or wireless communication links.